Check driving fatigue risk.
Driver fatigue is driven by four independent factors, and this score weights each. Time at the wheel matters, but so does total wakefulness — performance after 17 hours awake is comparable to a blood alcohol level of 0.05%, and after 21 hours to 0.08%. Sleep debt compounds it: a single night under seven hours measurably degrades reaction time the following day. Time since the last break has a strong effect because vigilance decays continuously, which is why two hours is the standard maximum block. The circadian penalty for driving between midnight and 6am reflects the fact that crash risk peaks in those hours regardless of how much sleep you had.
Driver Fatigue Checker
Score = hours driven x 6 + max(0, awake - 16) x 6 + max(0, 7 - sleep) x 8 + (minutes since break / 30) x 4 + 15 if night driving, capped at 100
This is an awareness aid, not a fitness-to-drive assessment. Fatigue impairment cannot be reliably self-judged, and drowsy driving is a major cause of fatal crashes. If you feel sleepy, stop and sleep — and commercial drivers must follow their applicable hours-of-service regulations.
It masks it for 20-30 minutes. Caffeine blocks the sensation of sleepiness without restoring vigilance, and the crash afterwards is worse. A 15-20 minute nap plus caffeine is far more effective than caffeine alone.
Professional rules cap daily driving at 9-11 hours with mandatory breaks, and that assumes a full night's sleep. For a private driver, 8 hours with a break every two is a sensible ceiling.